1. Field of the Invention
The present invention is used in systems where the source of power for low voltage electronics is a high voltage power supply.
2. Description of the Prior Art
In certain applications, the source of power for electronic circuitry is substantially higher than the operational voltage required by the electronic circuitry. For example, in aircraft, the available power supply voltage may be +28 volts, while the operational voltage for the electronic circuitry is +5 volts or +3.3 volts. As illustrated in FIG. 1, such systems usually employ a voltage regulator 10 interposed between the supply voltage 11 and the electronic circuitry 12 to provide the proper operating voltage to the electronic circuitry 12. When, for example, the supply voltage 11 is +28 volts and the operational voltage of the electronic circuitry 12 is +5 volts, the regulator 10 includes suitable circuitry which drops the supply voltage by 23 volts.
The type of regulator which is often used in such systems is a linear regulator. The large voltage difference between the supply voltage and the operating voltage of the electronic circuitry multiplied by the current consumed by the electronic circuitry results in a large amount of power being generated as heat in the regulator, and this power is essentially wasted. While the above-described heating problem may be overcome by use of a switching type regulator, such switching regulators are not always reliable at high operating temperatures, such as those encountered in downhole or jet aircraft applications.
A thermoelectric heat pump, which is commonly known as a Peltier thermoelectric heat pump, is a device that is semiconductor based, and the use of thermoelectric heat pumps to heat or cool electronic circuitry has been disclosed in U.S. Pat. Nos. 5,931,000; 5,079,618; 5,724,818; 2,984,077; and 5,887,435. However, none of the devices in the foregoing patents describe a system where the thermoelectric heat pump is driven by power that would otherwise be wasted. This advantageous result has been achieved by the apparatus of the present invention.